Field of the Invention
The present invention relates to a resin composition. Specifically, the present invention relates to a resin composition comprising a zinc oxide powder, and a prepreg and laminate prepared using the same.
Descriptions of the Related Art
Printed circuit boards are circuit substrates that are used for electronic devices to load other electronic components and to electrically connect the components to provide a stable circuit working environment. Thus, printed circuit boards require high thermal resistance, size stability, solder resistance, electrical properties, processability, etc. With the industrial development, the requirements for printed circuit boards in communication and computing electronic products (such as communication host, computer servers, etc.) and electrical products have increased. The aforementioned printed circuit boards usually have a multi-layered structure, and can be provided using the following methods: immersing a reinforcing material (e.g. glass fiber fabric) into a resin (e.g. epoxy resin); curing the immersed glass fiber fabric into a half-hardened state (i.e. B-stage) to obtain a prepreg; subsequently, superimposing the expected layers of the prepregs and superimposing a metal foil on at least one external surface of the superimposed prepregs to provide a superimposed object; hot-pressing the superimposed object (i.e. C-stage) to obtain a metal clad laminate; etching the metal foil on the surface of the metal clad laminate to form a defined circuit pattern; and finally, digging a plurality of holes on the metal clad laminate and plating these holes with a conductive material to form via holes to accomplish the preparation of the printed circuit board.
However, preparing printed circuit boards with multi-layered structures may lead to problems, such as bubbles in the resin and differences in junctional adhesion between different superimposed layers, which result in cracks or even popcorn condition (i.e., poor solder resistance) in the prepared printed circuit boards. Thus, spherical solid powders have been added to the resin composition to inhibit cracking in the boards. For example, U.S. Pat. No. 4,798,762 uses glass beads as spherical fillers to avoid rupture of the boards due to bending. However, the prepared boards have disadvantages that include poor size stability, poor electrical properties, etc. Furthermore, TW I264446 uses processed foaming microspheres as a filler to improve the properties of the laminate such as electrical properties, heat resistance, mechanical properties, etc. Nevertheless, the as-prepared laminates have limited application as the mass production cost of these foaming microspheres is high; and the Mohs hardness of the prepared laminate is so high that the pin of the drill will be rapidly worn during the drilling process of the laminate, and thus the lifetime of the drill is shortened.
In this regard, the present invention provides a resin composition for preparing a laminate, wherein the resin composition comprises a zinc oxide powder (preferably a spherical powder). The laminate prepared thereby is provided with outstanding properties such as size stability, heat resistance (high Td), electrical properties (low dielectric constant (Dk) and dissipation factor (Df)), etc. Cracking between the layers of the laminate can be advantageously inhibited (i.e., the laminate is provided with outstanding solder resistance).